A pupil at the San Fernando Royal Academy under the tutelage of Felipe de Castro, Gregorio Ferro was taught by Corrado Giaquinto and Anton Rafael Mengs, and was a faithful disciple and admirer of the latter. His canvases for San Francisco el Grande, the Monastery of the Incarnation and the Cathedral of Santiago led him to take up the post of Director General of the Academy in 1804. Earlier, in 1774, he designed this scene of the apostle and patron saint of the city in the battle of Clavijo for the tympanum of the Palace of the Rajoy family in the Plaza del Obradoiro in Santiago de Compostela. The drawing served as a model for the sculptures made by José Gambino and José Antonio Ferreiro between 1774 and 1776.

The Battle of Clavijo is a mythical and legendary episode of the Reconquest that would have taken place in the year 844 in Clavijo (Asturias) and in which the first intercession of Saint James the Apostle took place in favour of the Christians in the battle against the Muslims. This story is constructed from the 12th century onwards by mixing data from different battles and from this moment onwards the apostle of Spain will become a symbolic weapon of the first level with a great influence on the formation of the Spanish identity.